How to displace an object with a texture radially?
Like Gorgious indicated in the comments, the tutorial uses older Blender version where the displacement input in the Material Output node detects what it is, but in current version 2.83.4 the Material Output node's Displacement input only accepts a vector (3 values for x, y and z for displacement) so you need to use the new Displacement or Vector Displacement nodes that you can find in the Add menu -&gt; Vector. They will let you control the displacement faster and more conveniently then it used to be before.

What you see in the tutorial seems to be because the camera is placed above the plane being displaced and a short focal length is set for the camera lens so because of the perspective the displacement seems to go outwards from the center.